The principal objectives of this project are 1) to elucidate the mechanism involved in the development of the generator potentials of hair cells and 2) investigate the responses to acceleration of central nervous system neurons of Hermissenda crassicornis. Tilting of the preparation up to plus or minus 180 degrees caused a marked change in the noise as well as in the firing of the hair cells. With the same procedures, firing in the central neurons was observed. Transduction of sinusoidal acceleration of the cyst involves strong non-linearities causing two sharp responses per cycle whenever threshold is exceeded. These responses occur at the maximum of the applied force independently of the sign. This finding suggests that the transduction process is mediated by a critical bending of the hairs. Taps elicit large generator potentials in the hair cells at the top of the statocyst, while the hair cells at the bottom (which are covered by statoconia) respond weakly to this type of stimulus.